It is known from the prior art that reducing gas that is drawn off as top gas from a reducing zone after the reduction process is passed on for renewed use. In this respect, it is known that the top gas is first cleaned and the CO2 is separated from the top gas. By separating the CO2 and/or H2O, the production potential of the top gas can be increased and it can be used again for reduction.
The tail gas containing CO2 that is obtained during the CO2 cleaning has a varying composition. It is known from the prior art that the tail gas is thermally utilized, it being possible for the energy thereby produced to be used in the process.
A disadvantage of this is that there may still be considerable amounts of waste gas that have to be discharged into the atmosphere.